STANDARD SPECIFICATION FORSTRAIGHT-BEAM ULTRASONIC EXAMINATION

OF STEEL PLATES

SA-435/SA-435M

[Identical with ASTM Specification A 435/A 435M-90 (1996)]

1. Scope

1.1 This specification covers the procedure and ac-ceptance standards for straight-beam, pulse-echo, ultra-sonic examination of rolled fully killed carbon andalloy steel plates,1⁄2 in. [12.5 mm] and over in thickness.It was developed to assure delivery of steel plates freeof gross internal discontinuities such as pipe, ruptures,or laminations, and is to be used whenever the inquiry,contract, order, or specification states that the platesare to be subjected to ultrasonic examination.

1.2 Individuals performing examinations in accord-ance with this specification shall be qualified and certi-fied in accordance with the requirements of the latestedition of ASNT SNT-TC-1A or an equivalent acceptedstandard. An equivalent standard is one which coversthe qualification and certification of ultrasonic nonde-structive examination candidates and which is acceptableto the purchaser.

1.3 The values stated in either inch-pound units orSI units are to be regarded separately as standard.Within the text, the SI units are shown in brackets. Thevalues stated in each system are not exact equivalents,therefore, each system must be used independently ofthe other. Combining values from the two systems mayresult in nonconformance with the specification.

2. Referenced Document

2.1 ASNT Standard:SNT-TC-1A Recommended Practice for Personnel Quali-

fication and Certification in Nondestructive Testing

387

3. Apparatus

3.1 The manufacturer shall furnish suitable ultrasonicequipment and qualified personnel necessary for per-forming the test. The equipment shall be of the pulse-echo straight-beam type. The transducer is normally 1to 11⁄8 in. [25 to 30 mm] in diameter or 1 in [25 mm]square; however, any transducer having a minimumactive area of 0.7 in.2 [450 mm2] may be used. Thetest shall be performed by one of the following methods:direct contact, immersion, or liquid column coupling.

3.2 Other search units may be used for evaluatingand pinpointing indications.

4. Test Conditions

4.1 Conduct the examination in an area free ofoperations that interfere with proper functioning of theequipment.

4.2 Clean and smooth the plate surface sufficientlyto maintain a reference back reflection from the oppositeside of the plate at least 50% of the full scale duringscanning.

4.3 The surface of plates inspected by this methodmay be expected to contain a residue of oil or rust orboth. Any specified identification which is removedwhen grinding to achieve proper surface smoothnessshall be restored.

5. Procedure

5.1 Ultrasonic examination shall be made on eithermajor surface of the plate. Acceptance of defects in

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services

SA-435/SA-435M 2001 SECTION V

close proximity may require inspection from the secondmajor surface. Plates ordered in the quenched andtempered condition shall be tested following heattreatment.

5.2 A nominal test frequency of 21⁄4 MHz is recom-mended. Thickness, grain size, or microstructure of thematerial and nature of the equipment or method mayrequire a higher or lower test frequency. However,frequencies less than 1 MHz may be used only onagreement with the purchaser. A clear, easily interpretedtrace pattern should be produced during the examination.

5.3 Conduct the examination with a test frequencyand instrument adjustment that will produce a minimum50 to a maximum 75% of full scale reference backreflection from the opposite side of a sound area ofthe plate. While calibrating the instrument, sweep thecrystal along the plate surface for a distance of at least1T or 6 in. [150 mm], whichever is the greater, andnote the position of the back reflection. A shift inlocation of the back reflection during calibration shallbe cause for recalibration of the instrument.

5.4 Scanning shall be continuous along perpendiculargrid lines on nominal 9-in. [225-mm] centers, or atthe manufacturer’s option, shall be continuous alongparallel paths, transverse to the major plate axis, onnominal 4-in. [100-mm] centers, or shall be continuousalong parallel paths parallel to the major plate axis,on 3-in [75-mm] or smaller centers. A suitable couplantsuch as water, soluble oil, or glycerin, shall be used.

5.5 Scanning lines shall be measured from the centeror one corner of the plate. An additional path shall bescanned within 2 in. [50 mm] of all edges of the plateon the scanning surface.

5.6 Where grid scanning is performed and completeloss of back reflection accompanied by continuous

SUPPLEMENTARY REQUIREMENTS

The following shall apply only if specified in theorder:

S1.Instead of the scanning procedure specified by 5.4

388

indications is detected along a given grid line, theentire surface area of the squares adjacent to thisindication shall be scanned continuously. Where parallelpath scanning is performed and complete loss of backreflection accompanied by continuous indications isdetected, the entire surface area of a 9 by 9-in. [225by 225-mm] square centered on this indication shallbe scanned continuously. The true boundaries wherethis condition exists shall be established in either methodby the following technique: Move the transducer awayfrom the center of the discontinuity until the heightsof the back reflection and discontinuity indications areequal. Mark the plate at a point equivalent to the centerof the transducer. Repeat the operation to establish theboundary.

6. Acceptance Standards

6.1 Any discontinuity indication causing a total lossof back reflection which cannot be contained within acircle, the diameter of which is 3 in. [75 mm] or onehalf of the plate thickness, whichever is greater, isunacceptable.

6.2 The manufacturer reserves the right to discussrejectable ultrasonically tested plates with the purchaserwith the object of possible repair of the ultrasonicallyindicated defect before rejection of the plate.

6.3 The purchaser’s representative may witness thetest.

7. Marking

7.1 Plates accepted in accordance with this specifica-tion shall be identified by stamping or stenciling UT435 adjacent to marking required by the material speci-fication.

and 5.5, and as agreed upon between manufacturer andpurchaser, 100% of one major plate surface shall bescanned. Scanning shall be continuous along parallelpaths, transverse or parallel to the major plate axis,with not less than 10% overlap between each path.

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services